Taking insights from the fields of psychology and biology, a growing body of scholarship considers the psychophysiological foundations of political attitudes. Subconscious emotional reactions to threat, for example, have been shown to predict socially conservative attitudes toward out-groups. However, many of these studies fail to consider different sources of perceived threat. Using a combination of survey and physiological data, I distinguish between fear of others and fear of authority, finding that threat sensitivity predicts divergent political attitudes depending on the strength of each. Those who are more sensitive to threat from others tend to hold socially conservative attitudes, while those who fear authority generally take more libertarian positions. As sensitivity to threat is at least partially inherited, these findings highlight the genetic role of political predispositions.